


You'll Always Be Mine

by anxiousravenclaw



Series: Give Them What They Want [5]
Category: Bishoujo Senshi Sailor Moon | Pretty Guardian Sailor Moon, Bishoujo Senshi Sailor Moon | Pretty Guardian Sailor Moon (Anime & Manga)
Genre: Alternate Universe, Bittersweet, Bittersweet Ending, Consensual Sex, Crystal Tokyo Era, Explicit Consent, Explicit Fanart, Explicit Sexual Content, F/M, Inspired by Fanart, Loss of Virginity, Not Canon Compliant, Not to Be, One Shot, Plot What Plot/Porn Without Plot, Prompt Fic, She wants it, Smut, Technically cheating, Tragic Romance, Why do I keep doing cheating fics
Language: English
Status: Completed
Published: 2018-09-21
Updated: 2018-09-21
Packaged: 2019-07-07 21:11:13
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,163
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15916329
Author URL: https://archiveofourown.org/users/anxiousravenclaw/pseuds/anxiousravenclaw
Summary: In which Prince Demand captures Usagi and they share a passionate night together.(Also there is an explicit piece of fanart attached to this fic, not mine because I don't have that kind of talent, so be aware of that. I don't know. I felt like I had to give everyone a heads up XD)





	You'll Always Be Mine

**Author's Note:**

  * For [reader4books](https://archiveofourown.org/users/reader4books/gifts).



> I realize that Usagi really loves Mamoru and that Chibiusa will cease to exist if they don't get together but this is just a fun fic of this pairing that I decided to give a shot.
> 
> Oh and the underage tag is there since Usagi is a teenager and Prince Diamond is 18.  
> And yes I'm saying Diamond instead of Demand despite what the tag says cuz Prince Diamond sounds better XD

 

"You will always be mine. No matter who you love, who you marry, who you share your future with, you will always be mine." Prince Diamond whispered against her ear before moving his lips to press a sweet and lingering kiss against her temple. She shut her eyes, letting the tears escape as he felt the unspoken vow, the promise, of his love for her. She rolled towards her side, facing him, and hugging him close to her, dreading the moment when she'll have to let him go. Wishing it didn't have to end this way. But... she loved Mamoru, and even though she hadn't conceived her yet, hadn't birthed her yet, she already loved Chibiusa more then anything. She couldn't risk them, couldn't lose them. She couldn't lose Diamond either. But she knew she had to.

"You will always be mine, Usagi." Prince Diamond vowed as he pushed her bangs back, wiping away her tears. Usagi let a sob break through. He said "Usagi" and not "Neo Queen Serenity" and that almost broke her resolve. Almost. She did lean forward, pressing a kiss against his lips and trying to say with that one kiss how much she truly loved him, wanted to stay by his side, wanted him. But it was not to be. They both knew it. But she still said the words she knew he wanted to hear and wished was enough.

"Yes," she whispered, "I'm yours. I'll always be yours.

☆☆☆☆

It wasn't supposed to turn out this way.

When Usagi and the others had all traveled into the future to put a stop to the Black Moon Clan and their plans to destroy Crystal Tokyo. That was all she was prepared to do. She hadn't meant to fall in love with someone else.

Prince Diamond had ended up capturing her and she had been afraid as she had been separated from everyone and she had no idea what he even wanted with her. But he was nothing like she had expected.

"You look lovely in that dress." Usagi turned towards the voice, seeing nothing but a man's body in a white suit as he kept his face hidden in the shadows, before looking down and finding herself dressed in a dress she had never even seen before. She crossed her arms over her chest before aiming a glare at whoever this man was.

"Who are you?" She demanded.

The man merely chuckled as he started to walk into the light so Usagi could see his face now, her eyes widening and her mouth parting in surprise. The man was very handsome. He had silver hair that fell to the back of his neck and she saw that his eyes were a lovely hazel. But her eyes narrowed slightly at the Black Moon mark on his forehead, this man was their enemy and he was eyeing her as well, smiling at her softly.

"I'm Prince Diamond and I'm honored to have you here with me, Neo Queen Serenity." He gave her a slight bow, his eyes still locked on her.

"What? I'm not-"

"You might be younger now, but I would recognize your beauty anywhere." He had been walking towards as he was speaking until he was standing right before her, grabbing one of her hands and placing a kiss on her knuckles before smiling up at her coyling and causing her to blush a little and feeling a warmth deep in her belly she didn't understand.

"W-What do you want?" She asked a bit shakily as she pulled her hand back, holding it over her chest. The man, Prince Diamond, smiled down softly at her before reaching out a hand to cup her face delicately, almost lovingly, and Usagi felt herself freeze, her eyes widen, as he simply said, "You." Before leaning in to press a kiss softly against her lips.

She was confused, so confused. She wasn't completely sure what was happening or how this was all happening so fast. All she could seem to think about was how Prince Diamond's lips felt against her own. They were soft, yet slightly firmer, then she was expecting. And the kiss was both gentle yet demanding. And he kissed her in a way she wasn't quite used to. He had sucked in her bottom lip into his mouth, nibbling on it gently and licking along her lip before pushing his tongue through her parted lips, moving his tongue around the inside of her mouth, trying to reach every part of her mouth as if dying to taste every part of her. It was nothing like the somewhat tentative way Mamoru still kissed her.

Mamoru.

Usagi felt her heart clench as she thought of him and how hurt he'd be if he knew of this, not just of another man kissing her, but that she found herself enjoying it. And though she felt bad, felt utterly guilty and like she was betraying Mamoru and the future they were destined to live together, she couldn't help but return the kiss. She started moving her lip's against Diamond's, letting her own tongue explore his mouth and marveling at the feel, letting out little gasps and moans of pleasure from this deep and sensual kiss she was sharing with someone she didn't truly know.

Yet she still felt herself melting against him as he wrapped his firm arms around her waist, pulling her closer, and she broke free from the kiss slightly with a sharp gasp. She could feel something poking against her.

Prince Diamond moved to nuzzle his face against her neck while biting and sucking at her earlobe while he ground his hips against her, letting her feel his arousal even more. "Do you feel that, my queen," he whispered huskily against her ear, "that's all for you should you desire it."

Usagi felt her face heating up from embarrassment, and yet she couldn't bring herself to pull away, to push him away. It felt slightly wrong, and she knew that it was, but she didn't want it to stop.

"Ah!" Usagi gasped when she felt a hand groping at her ass and let her forehead fall against Diamond's shoulder, shivering and making small noises as her ass cheeks were being palmed and massaged.

"Do you want this?" Diamond whispered and Usagi whimpered as she bit down on her bottom lip, her fingers digging into his back and thinking about Mamoru. She shouldn't, she really shouldn't.

But she did.

Usagi gave in to her desires and jumped onto Prince Diamond, wrapping her legs around his waist and her arms around his neck, and started kissing him fiercely with him responding with equal vigor. He walked them over to the bed Usagi had been resting on and placed her down on her back without breaking the kiss and climbing on top of her. He groped at her breasts, teasing her nipples through the light material of her dress. Usagi whimpered at the sensation but arched her chest into his touch while also trying to get his white jacket off him. He broke the kiss to remove it himself and then leaned in to suck at the hollow of her throat, causing her to let out a low moan.

"So gorgeous." Diamond murmured against her flushed skin and Usagi glowed under the praise, no matter how wrong it was. She was still moaning and making soft sounds under his attention when she let out a surprised yelp when Diamond started to rip the dress off.

"Ah, wait!" She cried out but made no move to stop him, but this was happening so fast and she wasn't entirely ready.

"Is this your first time, my lovely queen?" Diamond asked, already having ripped the front of the dress off to reveal her small breasts and her perky pink nipples. Usagi flushed furiously when she realized just how much he was seeing of her and nodded. "Don't worry, I'll be gentle." He promised and Usagi merely nodded again, still slightly embarrassed but also still wanting this.

"Hah!" She gasped when Diamond placed his hands over her breasts, squeezing them and moving them under his hands and  occasionally twisting her nipples. Usagi unconsciously spread her legs open a little further, allowing Diamond to settle in between her legs. Once she lay panting underneath him he pulled his hands back to rip the dress completely off her, leaving her in nothing but the small white panties she still wore. Diamond looked down at her hooded eyes, blown wide with lust, the slight coloring on her cheeks, her long and blonde hair in their pigtails spread out around her, and the steady rise and fall of her bare chest, loving the sight of it all.

He trailed his fingers down her belly, twitching slightly from the touch, before slipping his fingers underneath the panties and into her soft folds. Usagi cried out, gripping the sheets and throwing her eyes wide open. It's an... odd feeling. Having someone else's fingers touching her there, but not entirely unpleasant. Especially once he starts twisting his fingers inside her.

Usagi arches off the bed slightly as she shuts her eyes and cries out as Prince Diamond strokes her silky walls and she can feel herself becoming wet from his touch. "You're enjoying this, aren't you?" He asked as he started to thrust his fingers into her.

"Ah! Y-Yes!" Usagi cried out, opening her legs more and moving her hips against his fingers to try and get more friction from them, wanting to feel more of what she was feeling. 

"I'm glad to hear that." Prince Diamond said as he pulled down his pants with his free hand, freeing his erection, moving her panties out of the way to reveal her wet and clicked cunt and carefully lining the head of his cock against her opening before gently and slowly pushing it in.

"Oh! Ah!" Usagi scrunched her face at the new and slightly painful stretch and her eyes began to tear a little, not from the slight pain, but from thoughts of Mamoru that were popping up. She had always pictured spending this moment with him. So then why...?

"Ah!" She moaned once he was fully inside her. She felt fingers trailing across the side of her face and opened her teary eyes to look up at Diamond. "Relax, it'll be better once you relax, and breath." He told her before leaning down to kiss her again. She responded to the kiss while also taking a deep breath through her nose while she tried to adjust to the feeling of him in her while Diamond struggled not to simply start taking her, rough and hard, like he wanted to. She felt so much better then he had ever imagined. She was so wet and so tight and her silky walls were so warm and constantly clenching around him as she tried to adjust to the feel of him and as much as he wanted to simply thrust into her and chase his pleasure in her willing and pliant body, he didn't want to hurt her. He wanted this to be pleasurable for her as well.

Once he felt that she had relaxed and was no longer scrunching her face from pain he gave an experimental roll of his hips and the smallest thrust he could. Usagi pulled back from the kiss and let out a loud gasp at the foreign sensation inside her. There was still an underlying sensation of pain, but it was overshadowed by the pleasure rolling inside and throughout her and found herself wanting more. But Diamond was moving in short and careful thrusts that were enough for her to feel and drive her on edge, but not enough to give her what she wants.

"M-More! Please!" Usagi cried out as she moved to cup at her own breasts and pinch her own nipples as she wrapped her legs around his waist. Diamond felt a rush of pleasure inside him when he heard her say that and snapped his hips forward, driving deeper into Usagi's warmth. "Oh my! Ah! Mnn, ah!" Usagi threw her arms over Diamond's neck, gripping at his white hair and burying her face against the side of his neck as he continuously drove into her, letting out little moans and noises as she breathed against his neck, encouraging Diamond to keep up the pace. He changed the angle of his thrusts slightly and Usagi nearly shouted out as she saw stars and encouraged him to keep hitting that place inside her. Diamond did and the room was quickly filled with the squelching sound of skin hitting against skin.

"Faster, faster! Almost there, almost there!" Usagi cried out, moving her hips against his and meeting each thrust, seeking completion. Diamond's thrusts started to stutter a bit and Usagi clenched around him as she came, throwing her head back and Diamond kept up his thrusts until he came as well, spilling deep inside her. Usagi fell back on the bed, breathing heavily and feeling more full then she ever thought possible. She didn't have much time to recover though as Diamond pulled out of her only to move her so she was on her knees, her face and chest pressed against the bed while Diamond held her hips up, moving the panties aside, which were already soaked with Usagi's slickness and his seed, and sliding his cock back inside her wet heat.

They both moaned and Usagi whimpered a little as he already started moving in her, the position allowing him to move deeper inside her and she found herself loving the sensation.

"Oh yes, yes, faster, harder, oh yes." Usagi gasped with every thrust that send her rocking forward and backward. Diamond grunted with every thrust, digging his fingers into her slender hips and snapping his hips harder, thrusting into her as hard as he could and loving the sounds coming out of her mouth and her words of encouragement and praises. He looked down, watching his cock moving in and out of her body, at the bare expanse of her creamy back, at the way she clenched at the sheets with every sharp thrust, how she arched her back and moved her hips back to meet his thrusts in perfect rhythm, wanting more of him and he was willing to give it to her.

He moved his hands to cup her breasts, that fit perfectly in his hands, and pulled her up so her back was flushed against his chest. She made a slight noise of surprise but made no protest as he sat back and placed her on his lap while still thrusting up into her.

"Oh! Hah, hah, hah!" Usagi let her head fall back against his shoulder, letting him bounce her on his lap, loving the feel of his cock moving in her and the way he fondles her breasts and she moved her face so he could kiss her, letting him shove his tongue into her mouth and sliding her tongue against his. "Mmm." She moaned as he thrusted harder inside her. "More, please. More, mmn, more." She pleaded and cried out as he moved one hand to rub and finger at her clitoris, this was an even more intense sensation and she felt another orgasm creeping on her. "More..." She breathed out and he rubbed hard against that nub, wanting nothing more then to give her everything she asked for. He thrust harder up into her and rubbed his thumb hard and held her close as she came again, this orgasm even more intense then her first one. He kept thrusting into her as she let her orgasm wash over her, sobbing at how over-sensitized her body felt until she heard him let out a low groan as he spilled deep inside her once again and she collapsed against him.

They sat there together, breathing deeply as they came down from their sexual highs. Prince Diamond began to finger her, feeling how wet she still was from her slick and his seed as it dripped down from her and onto him. Usagi made a soft noise at this, not quite minding but not use to the full feeling as he still had his softening cock in her. It was only when she felt him trying to push his seed back in her that she spoke.

"Don't."

Usagi felt his fingers twitch, the ones still inside her and the one grabbing at her right breast.

"I love you, you know. You must know that? I could give you everything, without question. Stay with me, my queen."

Usagi shook her head. "I'm not a queen-"

"Not yet. But you will be."

"I love Mamoru." She said as she looked up at the ceiling. She wouldn't cry. She won't let herself think about how she betrayed him. She didn't want to completely ruin this moment, but she had to let him know.

"He'll never love you as I do." Prince Diamond swore and Usagi turned her face around enough so she could look at him sadly. She brought her left hand up to rest against his face and placed her right hand just under his wrist and looked deeply into his eyes, seeing the sadness and fierce desire in him. But her heart already belonged to someone else. To two people. And she couldn't risk losing her future daughter. She couldn't.

This was nothing but a sexual desire she had no control over and let herself fall into without thought. And now she had to hurt him. Hurt him, and keep it a secret from everyone so Mamoru will never know. She loved this short time she had with Prince Diamond... but nothing will come from it.

She kissed him softly and allowed him to pull her into bed beside him. Let him wrap her in his arms and remove her soaked and ruined panties. Let him promise her the world. And once he was down trying to convince her to stay with him she cried. She cried for having to hurt him, for knowing that some part of her will always yearn for him but knowing it could never be. She cried for what could have been.

"You'll always be mine." He whispered again as she prepared to leave, to go looking for Mamoru and the others.

"I know." Usagi agreed and let him kiss her goodbye one final time for neither of them knew that soon Usagi will cry out when Diamond jumps in front of her, sacrificing himself for her by protecting her from an attack and dying in her arms and she will cry for him and no one will understand why she is so distraught over his death or why he did what he did.

But Diamond will know. And Usagi will know.

That it was all done because she will always be his and he will always be hers.

**Author's Note:**

> Any prompt requests just leave a comment and I'll see whether or not I can do it :)


End file.
